I've had several AK's (still have a Galil), several AR-15's, and a few AR-180's. Not too long ago I picked up an AR-180B and love it due to its being clean piston driven, using many easily available AR-15 parts, being accurate, reliable and being able to add a folding stock. Other than my Galil, it is my favorite semi-auto of the group listed.
The other day I was talking to a gun shop retailer and he said that the AR-180B is very hard to sell. Anyone have a clue as to why that would be the case?